login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A173280 First column of the matrix power A173279(.,.)^j in the limit j->infinity. 3
1, 1, 3, 7, 29, 129, 757, 5185, 41155, 368351, 3671635, 40295943, 482758111, 6268066531, 87668492115, 1314023850727, 21011431917453, 357014074280785, 6423561495057421, 122004755658629081, 2439367774898883497, 51213663674167659301, 1126452985959434543237 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

We can generalize A173279 to other matrices derived from some sequence S by Smat(n,k) := S(n-r*k), r >= 2,

and find that they define sequences B(x) via S(x)= B(X)/B(x^r), b(n) = Sum_{t=0..n, n-t == 0 (mod r)} S(t)*B_{(n-t)/r}.

The sequence here is the case of S=A000142 and r=2.

LINKS

Table of n, a(n) for n=0..22.

FORMULA

A000142(x) = A(x)/A(x^2), where A(x) and A000142(x) are the o.g.f.'s associated with A000142 and this sequence here.

Sum_{n>=0} 1/a(n) = 2.519966353393413186683398448854995831308...

a(n) = (A173279^j)(n,0).

a(n) = Sum_{t=0..n, n-t even} t!*a_{(n-t)/2}. - R. J. Mathar, Feb 22 2010

MAPLE

A173280 := proc(n) option remember; local a, l; if n = 0 then 1; else a :=0 ; for l from n to 0 by -2 do a := a+ l!*procname((n-l)/2) : end do ; a ; end if; end proc:

seq(A173280(n), n=0..60) ; # R. J. Mathar, Feb 22 2010

CROSSREFS

Cf. A000142.

Sequence in context: A110613 A088095 A217576 * A141477 A211371 A302157

Adjacent sequences:  A173277 A173278 A173279 * A173281 A173282 A173283

KEYWORD

nonn

AUTHOR

Gary W. Adamson, Feb 14 2010

EXTENSIONS

Extended, and invalid comment on convergence to e removed, by R. J. Mathar, Feb 22 2010

Index of B in the convolution formula in the comment corrected by R. J. Mathar, Mar 23 2010

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 24 09:29 EDT 2019. Contains 321448 sequences. (Running on oeis4.)